XP on my iMAC

I have a iMAC running OSX 10.6.7 and my boot camp assistant is 3.0.4 (325) i tried to install xp sp3 and it got so far then stopped i have read another thread that says later versions of a MAC won't install xp only vista or win 7 is this right ,i do remember a box coming up and saying insert vista or win 7 disk and thought nothing of it.

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